Food Chains/ Food Webs

Producers (Autotroph)- Organisms that make their own food

•Photoautotrophs•Use sunlight to make energy( food)

•Chemoautotrophs

•Use chemicals to make energy (food) by converting energy from inorganic molecules

Measuring Productivity

Biomass is the organic material that has been produced in an ecosystem

*Consumers (Heterotrophs) –Organisms that must eat other organisms as food for energy

4 types of heterotrophs

1. Herbivoreeats plants

2. Carnivore-eats animals

Cow eating grass

Lion eating a zebra

3. Decomposerbreaks down dead organic matter (specialized detritivore)

4. Omnivore-eats plants and

animals

Mushrooms are decomposers

Bears mainly eat berries and fish

Energy Flow-Food Chains The passage of energy

through an ecosystem

One organism eats another

Producers are always the first level

Each step in the chain is a trophic level

Food weblinks all the food chains together

Energy Pyramid

Only about 10 %of the Energy in one trophic level is transferred to the next.

100%

1%

10%

Limitations of Trophic levels – ecosystems rarely contain more than a few trophic levels because the energy is transferred very slowly.

What is left is released as heat into the environment.

Energy Pyramid

Fourth trophic level

Third trophic level

Second trophic level

First trophic level

Tertiary consumers

Secondary consumers

Primary consumers

Producers